WO1998030460A1

WO1998030460A1 - Sealing clip for bags and tubes, and matrix for sealing the latter

Info

Publication number: WO1998030460A1
Application number: PCT/EP1998/000022
Authority: WO
Inventors: Jürgen Hanten; Gerhard Lapp; Manfred Metzler; Jürgen Reitz; Günter Vermehren
Original assignee: Poly-Clip System Gmbh & Co. Kg
Priority date: 1997-01-11
Filing date: 1998-01-06
Publication date: 1998-07-16
Also published as: EP0951427A1; DE19700692A1; US6401306B1; DE59801440D1; ES2162412T3; AU5765598A; EP0951427B1

Abstract

The invention concerns a sealing clip (10) for bags, foil tubes or the like, said sealing clip (10) comprising a wire section, a pre-curved clip base (12) and two clip legs (14) adjoining the latter on both sides. The two clip legs taper constantly from their clip base ends to their free ends. The invention also concerns a wire section for sealing clips of this type which tapers constantly towards both ends. The invention finally concerns a matrix (30) for sealing the sealing clip and having two slide channels (36, 38) which each narrow conically from an inlet point.

Description

Closure clip for bags and hoses and matrix for their processing

The invention relates to a closure clip for bags, film tubes or the like, consisting of a wire section, with a pre-bent clip base and two clip legs adjoining this on both sides. The invention further relates to a wire section for the closure clip and to a die having two sliding grooves for closing the closure clip.

Simple closure clips consisting of a wire section can be produced in that an endless wire is fed to a sealing machine, a section of which is separated from the wire in the sealing machine and the wire section is finally bent, for example, around a bag braid to be closed. It is also known to feed a closing machine, not endless wire, but already separate wire sections. The wire sections can be straight or pre-shaped in a U-shape. For magazining, these wire sections are generally fastened next to one another on a carrier tape, so that they form a magazine strand. The advantage of such closure clips formed from a wire section lies in the simple manufacture of these closure clips. The tightness of the closures that can be achieved with the known closure clips consisting of a wire section, on the other hand, leaves something to be desired. Closing machines which have a stamp and a die are usually used as a tool for closing the said closure valves. The U-shaped pre-bent locking clip is first taken from a magazine by the stamp and guided against rotation. Then the punch and die are moved towards each other. During this movement, the closure clip encircles the packaging material gathered into a braid. Then reach the free ends of the inn! the locking clip the die first and are guided in the course of the further movement of sliding grooves in the die. The legs of the locking clip are plastically deformed, so that there is finally a more or less circular closed locking clip.

Matrices are known which have two semicircular sliding grooves arranged parallel to one another. The main plane of the two slide rails is slightly inclined with respect to the main plane of the locking clip, so that each sliding groove has an entry point which lies in the main plane of the locking clip. The main plane is the plane in which the center line of a slide groove or the locking clip runs. If the locking clip guided by a punch is moved against the die for locking, each of the free leg ends enters a respective sliding groove at a respective entry point and is guided by this on a helical track caused by the inclination of the sliding grooves. As a result, the two free ends of the closure clip slide past one another when being closed, so that after the closure they overlap laterally and lie parallel to one another.

It is the object underlying this invention to provide a closure clip consisting of a wire section, with which denser closures can be achieved than with the previously known closure chambers,

The solution to this problem consists, according to the invention, in a closure clip of the type mentioned at the outset, which is characterized in that the two Kiammer legs taper continuously from their ends on the clamp base side toward their free ends. The victory is based on the knowledge that a closure clip made of a wire with a uniform cross-section always bends particularly strongly in the area of the arc sections between the legs and the clip base because the bending stress is greatest there. Therefore, closure clips consisting of a wire section of uniform cross-section never take the ideal for tight closures Circular shape. Due to the tapering wire cross-section of the closure clip according to the invention, the bending stress is distributed much more evenly over the entire length of the legs, so that the closure clip almost assumes the ideal circular shape when closed.

Preferably, the bottom of the clip and the clip leg! the locking clip has a round cross section. Such a closure clip can be produced in a simple and inexpensive manner from a piece of round wire which is partially stretched, so that the tapered legs result.

In a preferred embodiment of the closure clip, the clip base is preformed in a circular arc. The arch-shaped preforming of the clip base supports the approach of the clip to the ideal circular shape when closing.

Furthermore, a locking chamber is preferred which has a shoulder on the outer radius of the clamp base. With the help of such an approach, the closure clip can be guided in the stamp in a rotationally secure manner when closing.

The solution to the problem on which the invention is based also consists in a wire section for the closure clips according to the invention, which is characterized in that the wire section tapers continuously toward its two ends. Such a wire section achieves the object according to the invention in particular in connection with machines of this type, to which straight, not pre-bent wire sections are fed. In this case, the individual wire sections are first bent into a U shape in the closing machine (DE 41 20 440).

In the case of a straight wire section, it is particularly advantageous if the cross section of the wire section decreases continuously from the center of the wire section to its two ends, so that the wire section tapers on both sides in the region of its later clamp base. In this way, the wire section in the area of the base of the clip is evenly subjected to bending during preforming and therefore easily assumes an arcuate shape.

According to the invention, a die of the type mentioned at the beginning also contributes to achieving the object, the two sliding grooves narrowing conically starting from one entry point each. Such a matrix has the advantage that the Tapering clamp legs of the closure clip according to the invention are guided closer together when closing than with conventional dies. In addition, the die can be made narrower, so that only a smaller space has to be provided in the closing machine for the die. Closure chambers closed with the die according to the invention take up less space on the packaging sleeve gathered together to form a braid, so that less packaging sleeves are needed for the closure.

In a preferred embodiment of the die, the die is designed in such a way that the centers of curvature of the sliding grooves are mirror-symmetrically offset from the center of the recess and their parallel axes are inclined more weakly than the axis of the rib relative to the axis of the recess. The result of this is that the tapered ends of the clamp legs are pressed more firmly against the packaging sleeve, which is gathered into a braid, and laterally against one another when they are closed.

Embodiments of the invention will now be explained with reference to the drawings. These show:

Figure 1 is a closure clip according to the invention with tapered legs and a round cross-section.

FIG. 2 shows a modification of the closure clip from FIG. 1 with an arcuate clip base with an attachment; FIG.

3 shows a wire section for the closure clips from FIGS. 1 and 2;

FIG. 4 shows a variant of the wire section from FIG. 3;

5a to C show different views or partial sections of a known die for closing the closure clips from FIGS. 1 and 2;

6 shows a closed closure clip according to the prior art in side view (and top view);

7a and b a new die in plan view and partial section;

FIG. 8 shows a closure chamber closed with the die from FIG. 7 with tapered legs. The variant of a closure clip 10 shown in FIG. 1 has a preformed clip base 12, to which a leg 14 is connected on both sides. Clip base 12 and leg 14 each have a round cross section. This steadily decreases in the legs 14 starting from their ends on the clamp base side towards their free ends. Ideally, the tapered legs 14 each form a carrier of the same bending stress when the closure clip from FIG. 1 is closed, so that they round evenly when closed.

It is envisaged to guide the leg loops so that they slide past one another so that the free ends of the legs 14 partially overlap laterally after the closure. A closure clip 10 which is closed in this way has only a slight tendency to spring open under the influence of the internal pressure exerted by the packaging material. In addition, differing braid diameters are compensated for by the fact that the leg ends overlap to different extents after the closure. In this way, a wide range of different plait diameters can be covered with a closure clip geometry. This simplifies storage, since only a few variants of the closure clip 10 have to be kept in stock.

FIG. 2 shows a variant of the closure clip 10 from FIG. 1, in which the clip base 12 'is not flattened in the middle, but has a circular arc shape. In addition, the clip base 1 2 'is equipped on its outer radius with a shoulder 16, which makes it possible to precisely guide the closing clip 10' during closing by the shoulder 16 engaging in a corresponding groove in a closing tool. In particular, this prevents the locking clip 10 'from twisting during closing.

It can also be seen from FIG. 2 that the clamp base 1 2 'and the legs 14' do not have a round cross section, but - with the exception of the area of the attachment 16 - a hexagonal one.

Figures 3 and 4 each show a wire section 20 and 20 ', from which closure clips of the type shown in Fig. 1 or similar can be formed. The wire section 20 from FIG. 3 has a cylindrical middle piece, to which end sections 24 which are tapered on both sides towards the ends are connected. The middle piece 22 is provided to be pre-shaped in a U-shape are so that it forms a bracket base such as the closing bracket 10 of FIG. 1. The end sections 24 of the wire section 20 then form the legs 14 of the locking clip 10.

The wire section 20 can be preformed into the open closure clip 10 outside the sealing machine, for example at the closure clip manufacturer. The closing chamber is then - possibly as part of a magazine strand - fed to the closing machine in the preformed state.

The preforming of the closing chamber 10 can, however, also only take place within the closing machine before the actual closing process. In the latter case, a wire section is fed to the sealing machine in the stretched state. The wire section 20 'according to FIG. 4 is particularly suitable for this case. The wire section 20 'tapers continuously from its center to its two ends. It practically consists of only two conical end sections 24 '; a cylindrical middle piece 22 as in the wire section 20 is omitted. In this way, the middle region of the wire section 20 'which later forms the clamp base 1 2 already represents a carrier of the same bending stress, which easily assumes a uniformly round shape during preforming in the sealing machine. The end regions of the wire section 20 'forming the clamp legs 24' remain stretched. They are only bent around the braid to be closed when the closure chamber is closed. Since also the Klammerschenke! 24 'represent a carrier of uniform bending stress, they also assume the ideal circular arc shape when closed.

FIGS. 5a to c show a known die 30 of a tool for closing closure clips according to FIGS. 1 and 2. FIGS. 5b and 5c represent the cuts designated in FIGS. 5a.

The die 30 has a recess in the form of a partially cylindrical recess 32. Two immediately adjacent, parallel sliding grooves 36 and 38 are milled into the wall 34 thereof. Both sliding grooves 36, 38 have the shape of an arc of the same radius, are also rounded in cross section and form a rib 35 between them. The centers of both arcs also lie on a common center axis 40 which intersects the cylinder axis 42 of the recess 32. The central axis 40 is inclined relative to the cylinder axis 42 (for example at an angle of 1 2 °) that the entry points 44 and 46 of the gliding rollers. 36, 38, ie their apexes lie approximately in the central plane 48 of the die 30, which is perpendicular to the cylinder axis 42. The manufacture of both sliding grooves 36, 38 takes place with a one-piece milling cutter which is pivoted about the above-mentioned inclination angle about the vertical axis defined by the intersection of the cylinder axis 42 with the central plane 48.

To close a closure clip 10, it is fed from a stamp onto the die 30. The free leg ends of the closure clip 10 get into the two sliding grooves 36, 38 at the entry points 44, 46 and are guided by the sliding grooves 36, 38 during the further movement of the stamp. The clamp legs 14 of the closure clip 10 are bent in a circular arc and at the same time are guided past one another in parallel by the sliding grooves 36, 38, so that the closed closure clip according to the prior art assumes the shape shown in FIG. 6 with laterally overlapping, parallel abutting leg ends.

If, however, the die 30 from FIG. 5 were used to close the closure clip 10 in FIG. 1, the tapering clip leg ends would not be brought together so closely that they would finally abut one another laterally.

1 is therefore preferably used to close the closure clip 10 from FIG. 1. The die 30 'also has two sliding grooves 36' and 38 ', the main planes 37', 39 'of which run parallel to one another, but are less inclined relative to the central plane 48' compared to FIG. 5, with the inclination of the rib 35 'unchanged are. At the same time, the center points M2 and M3, and thus the axes of rotation 40 ', 40 "perpendicular to the main planes 37 ^' , 39 ', are offset parallel to one another, in mirror images to both sides of the axis 40, which are at the same angle to the axes of rotation 40' , 40 ", which the rib 35 'encloses with the main planes 37', 39 '.

This and the manufacture of the sliding lines 36 ', 38' with individual milling cutters offset by the distance M2-M3 do not change the fact that the emiauf points 44 'and 46' of the casting grooves 36 ', 38' lie in the central plane 48 '. In contrast to the slide grooves of the known matrices (eg die 30 from FIG. 5), however, the casting grooves 36 'and 38' are steadily narrower starting from their entry points 44 'and 46', so that the width of the casting grooves 36 'and 38' in Ideally, the respective width of the tapered clip legs 14 of the closing clip 10 equivalent. As a result, the clamp legs 14 are brought closer together during closure and lie laterally close to one another when the closure clamp 10 is closed. However, this narrowing of the sliding groove width from the entry point to the exit point (with which the 'pivoting back' of its main planes 37 ', 39' towards the central plane 48 'corresponds) means that the width of the die 30' - transverse to the central plane 48 ' - Can be significantly lower than that of the known die 30 (Fig. 5), which has the advantages described above. It is also advantageous that, due to the geometry described above, each slide groove runs out to a smaller depth at its outlet point, with the further consequence that the legs 14 of the closure clip 10 are pressed more firmly against the packaging sleeve braid to be closed when closing.

One of many conceivable modifications of the matrices 30 and 30 'is to provide sliding grooves which do not run on a circular path, but on a spiral path, so that the respective entry point of a sliding groove lies on a larger radius than the corresponding end point of the sliding groove.

Due to the described and other variations of the die, the shape of the closed locking clip can be adapted to a wide variety of uses.

FIG. 8 shows a side view of the result of a closing process when a closing chamber according to FIG. 4 is processed with a die according to FIG. 7.

Claims

PATENT CLAIMS

1 . Closure clip for bags, film tubes or the like, consisting of a wire section (20), with a pre-bent clip base (1 2) and two clip legs (14) adjoining this on both sides, characterized in that the two clip legs! (14, 1 4 ') taper continuously from their ends on the staple base towards their free ends.

2. Closure clip according to claim 1, characterized in that the clip base (1 2) and the clip legs (14) have a round cross section.

3. Closure clip according to one of the preceding claims, characterized in that the preforming of the clip base (12) is a circular arc.

4. Closure clip according to one of the preceding claims, characterized in that an attachment (16) is provided on the outside of the clip base (1 2 ').

5. Wire section for closure clips according to claim 1, characterized in that the wire section (20, 20 ') from the ends of the clip base part tapers continuously towards both free ends.

6. wire section for closure clips according to claim 1, characterized in that the cross section of the wire section (20 ') from the center of the wire section (20') to its two free ends steadily decreases.

7. die for closing a closure clip according to claim 1, which has a substantially partially cylindrical recess (32) and therein two parallel, inclined towards the main plane of the clamp base and the recess correspondingly curved casting grooves (36, 38), each with an entry point (44, 46 ) and an outlet point (45, 47), characterized in that both casting grooves (36 ', 38') narrow conically from their respective entry point (44 ', 46') to their respective exit point (45 ', 47').

8. Die according to claim 7, characterized in that the centers of curvature (M2, M3) of the sliding grooves (36 ', 38') are mirror images offset from the center (M1) of the recess and their parallel axes (40 ', 42 ") against Axis (42 ') of the recess (32') are inclined less than the axis (40) of the rib (35) ').